Real Madrid have opened disciplinary proceedings against Federico Valverde and Aurelien Tchouameni after a series of bust-ups between the players including one that saw Valverde taken to hospital.
The team-mates were involved in a physical confrontation at the end of training on Wednesday and tempers flared again in training on Thursday.
Valverde was taken to hospital with a suspected head injury, but was quickly discharged and returned to the club's Valdebebas training ground.
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Real Madrid's players held a crisis meeting after the incident, with the club later confirming an investigation - led by president Florentino Perez - was under way.
A statement read: "Real Madrid CF announces that, following the events that took place this morning in the first team training session, it has decided to open disciplinary proceedings against our players Federico Valverde and Aurélien Tchouameni.
"The club will announce the resolutions of both cases in due course, once the corresponding internal procedures have been completed."
The incidents have taken place in the build-up to the Clasico in Barcelona on Sunday, with Barcelona 11 points clear of Real Madrid at the top of LaLiga and needing only one point to clinch the title.
The news comes at the end of a tumultuous day after fan unrest with forward Kylian Mbappe spiralled.
Mbappe is on track to feature on Sunday following a hamstring injury but a petition to see the French forward sold reached 30 million signatures on Thursday.
Analysis: Why are fans unhappy with Mbappe?
Real Madrid are not going to win a trophy again this season, but the fans are particularly unhappy about the fact Mbappe flew off in a private jet to Sardinia for a romantic break with his actress girlfriend, Ester Exposito, last week when he was recovering from a hamstring injury.
He returned to Madrid on Sunday evening just minutes before Real Madrid kicked off away at Espanyol and it has not gone down well with Real Madrid so far behind their great rivals, Barcelona. There is an El Clasico on Sunday at the Camp Nou and it is likely Barcelona will be crowned LaLiga champions again. Meanwhile, Real's star player has been off on holiday.
His representatives have made it clear the player had permission to go away for a few days and he is following the rehabilitation programme which has been put in place for him by Real Madrid's medical team.
But despite that, the frustration in Madrid appears to be growing.
An online petition for Real Madrid to get rid of Mbappe has grown rapidly and if the 30 million signatures are all genuine people, that would make it a world record-breaking petition.
Despite Mbappe's goals, Real Madrid have not won a major trophy since he joined them on a free transfer from Paris Saint-Germain two summers ago.
To make matters worse, PSG won the Champions League for the first time in the season after he left and they are back in the final later this month.
Mbappe is an incredible talent but his lack of work-rate off the ball meant PSG boss Luis Enrique, who is arguably the best manager in the world right now, was not that unhappy when he left. For Luis Enrique, the team always come first and if you don't run, you don't play.
If you watch Mbappe play, he is the kind of player who, when his side doesn't have the ball, he does very little. He hangs around the centre circle waiting for someone to pass to him and in modern football, that doesn't work.
PSG were more than happy when 'the Mbappe circus' left town and relations were so toxic that the player and his former club have been involved in a long-running financial dispute about the terms of his contract and his departure.
Also, Real Madrid fans are asking the question again and again: can we have a side with Vincius Jr and Mbappe in it? There's no balance if you have both of those players in the side. That's another reason why we have seen this petition and why some Real fans want to get rid of Mbappe.
(c) Sky Sports 2026: Aurelien Tchouameni and Federico Valderde: Real Madrid players hold crisis meeting after training ground fight sees Valderde sent to hospital
Kylian Mbappe Q&A: Why have over 30m Real Madrid 'fans' signed petition for striker's exit?
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